1. Field of the Invention
This invention broadly relates to a class of adjustable locking pliers (such as the type utilizing a locking toggle), and more narrowly relates to adjustable locking pliers embodying opposing jaw members having parallel relationship (being also categorized as toggle wrenches), with handles economically constructed incorporating an ergonomic design.
2. Description of Related Art including information disclosed under 37 CFR 1.97 and 1.98
Well known to the art are conventional locking pliers having opposing jaw members communicating pivotally - with a movable jaw member applying clamping force by its levered rotation around a central point housed in the body of the conventional locking pliers. Known to the art are parallel grip pliers having opposing jaw members communicating pivotally in an adjustable parallel relationship - with a movable jaw member applying clamping force by its levered rotation around multiple points housed in the body of the parallel grip pliers. Also known in the art are parallel action toggle wrenches having opposing jaw members communicating slidable in an adjustable parallel relationship - with a movable lower jaw member slidable and secured to parallel opposing outer side edge length dimensions of a rectangularly shaped support member.
As it is known in the prior art concerning the type of pliers above-mentioned, all parallel action toggle wrenches have in common a movable lower jaw member constructed with parallel opposing structures slidable and contacting and pressuring parallel opposing outer side edge length dimensions of a rectangularly shaped support member - resulting in a tendency for the movable lower jaw member to bind (while opposing jaw members are under pressure) along the above-mentioned outer side edge length dimensions of the rectangularly shaped support member. This binding pressure makes releasing the movable lower jaw member from the outer side edge length dimensions of the rectangularly shaped support member difficult during the release of clamping pressure from the clamped object.
In contemplation of the Specification, the prior art has not provided adjustable toggle locking pliers embodying parallel opposing jaw members utilizing a substantially rectangular shape support member section with mechanisms of releasing clamping pressure more closely resembling the release of clamping pressure employed by conventional toggle locking pliers.
(1) Disadvantages of Conventional Locking Pliers and/or Automatic Adjusting Locking Pliers:
(a) Jaw members not in parallel relationship - resulting in jaw slippage from less surface area contact with object (or objects) being clamped.
(b) Width adjustment between handles (toggle angle adjustment) being difficult to determine and keep secured during clamping/releasing procedure - resulting in an awkward over adjustment and subsequent readjustment of adjustment screw and/or toggle stop screw.
(2) Disadvantages of Parallel Grip Pliers:
(a) A movable lower handle located below its fixed upper handle - resulting in a reduction of mechanical advantage - when compared to pliers having a movable upper handle located over a fixed lower handle (as in tongue and groove slip-joint pliers).
(b) Handle construction being not of ergonomic/economic design - results in awkwardness during handle operation by the reduction of hand grip.
(3) Disadvantages of Parallel Action Toggle Wrenches:
(a) Handle construction being not of ergonomic/economic design - results in awkwardness during handle operation by the reduction of hand grip.
(b) Toggle release lever upper handle design being partially housed slidable in a lower handle design - results in awkwardness during the clamping/releasing procedure from the subsequent increased lower handle width dimension (width dimension measured from either top or bottom view).
(c) Lower handle design having an externally mounted toggle adjustment assembly - results in uncomfortableness during handle operation by the reduction of hand grip.
(d) Movable lower jaw member design has rigidly mountable parallel opposing structures slidable and binding along parallel opposing side edge lengthwise dimensions of a rectangularly shaped support member.
The disadvantages of conventional and/or parallel locking pliers are the difficulty in determining the readjustment of the locking toggle before different size objects are clamped; and cost of manufacture.
(4) The disadvantages of automatic self-sizing locking pliers are:
(a) The awkward release of the locking mechanism.
(b) The awkward position of the locking mechanism when in the unlocked mode.
(c) Jaw members being not parallel when clamped.